Serial Data Transmission (Synchronous Mode): Figure 15.19 shows a sample flowchart for
serial transmission.
Use the following procedure for serial data transmission after enabling the SCI for transmission.
1. SCI status check and transmit
Start of transmission
data write: Read SCSSR1 and
check that the TDRE flag is set to
1, then write transmit data to
SCTDR1 and clear the TDRE flag
Read TDRE flag in SCSSR1
to 0.
No
2. To continue serial transmission,
be sure to read 1 from the TDRE
flag to confirm that writing is
possible, then write data to
SCTDR1, and then clear the
TDRE flag to 0. (Checking and
clearing of the TDRE flag is
automatic when the direct
memory access controller
(DMAC) is activated by a
TDRE = 1?
Yes
Write transmit data to SCTDR1
and clear TDRE flag
in SCSSR1 to 0
No
No
transmit-data-empty interrupt
(TXI) request, and data is written
to SCTDR1.)
All data transmitted?
Yes
Read TEND flag in SCSSR1
TEND = 1?
Yes
Clear TE bit in SCSCR1 to 0
End
Figure 15.19 Sample Serial Transmission Flowchart
Rev. 6.0, 07/02, page 645 of 986
RENESAS [ RENESAS TECHNOLOGY CORP ]
